The passing of “first flatus” is a common medical indicator that helps surgeons decide when to begin feeding patients who have undergone abdominal procedures. Patients with a history of prior intestinal resection, perforation or abscess with sepsis, short gut, or intestinal hypomotility disorders, are typically not eligible to resume feeding until the passing of “first flatus” for safety reasons. Additionally, patients that have undergone complicated non-elective (emergency) abdominal procedures, suffer from cognitive impairments, or are at high risk of developing aspiration pneumonia, are also not eligible to resume feeding until the passing of “first flatus”. For patients with prior intestinal resection or those that have undergone abdominal procedures (and are not trustworthy historians e.g. young children, demented patients, and the like), determining if a patient has passed “first flatus” is very important. However, it may be difficult for a clinician to determine when “first flatus” has passed and when to initiate feeding.
Feeding some patients too early can result in life-threatening complications leading to death, or dramatically lengthened hospital stays. Waiting too long to feed some patients can also increase the length of a hospital stay. Through determination of whether and when a patient has passed “first flatus”, a more efficient and efficacious patient recovery plan may be implemented.
Bowel motility can be determined by placing a stethoscope on a patient's abdomen and listening for indications of motility. However, such a determination is not a reliable means of determining whether or not there is normal bowel motility, or whether an obstruction in the intestines is present.
The percent of carbon dioxide in flatus is about 5-80% and usually about 10-30% (Calloway, D. H. (1968). Gas in the alimentary canal; in Handbook of Physiology (ed. C. F. Code), section 6, volume 5, chapter 137, page 2839, Washington D.C.: American Physiological Society). Flatus typically contains higher concentrations of carbon dioxide than what is in the atmosphere, and almost always contains hydrogen gas that is in significantly higher concentrations than what is in the atmosphere. As such, when carbon dioxide is detected by the carbon dioxide detector at concentrations significantly higher than that of atmospheric levels, then the passing of flatus is deemed to have occurred. The passing of flatus has been be determined using a carbon dioxide detector (Yukioka H. et al., Br J Anaesth, 1987, 59(5): 581-584). However, the particular carbon dioxide detector disclosed by Yukioka et al. is not a practical inexpensive device capable of detecting flatus on a routine basis in a hospital, nursing home, or community setting.